Fitbit and gym for 2wk: Calorie deficit but no weight loss?

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jobriath
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Fitbit and gym for 2wk: Calorie deficit but no weight loss?

Postby jobriath » Mon Aug 21, 2017 3:12 pm UTC

Hi guys!

My partner has been using fitbit's diet and exercise tracker in a bid to lose weight. We are also walking a lot more and going to the gym for a combination of weight training and cardio (emphasis on weight training). Altogether she's aiming for 500 Calorie deficit per day, which should translate into about 0.5kg (1lb) weight loss per week. We've been doing this for two weeks.

First week she lost 0.2kg. This week she has lost 0.1kg. This is significantly less weight loss than expected and I wanted to check others' experiences. Reasons I can think of:
* Starting weightlifting from zero increases muscle water retention. Would this be significant after a couple of weeks?
* Fitbit is underestimating Calorie-counts.
* Fitbit is overestimating exercise effects. Its counts do seem high, especially for random bouts of walking...
* Fitbit is overestimating Base Metabolic Rate.
* Ladytime is on the horizon---more water retention?
* It's just been two weeks and there's a lot of noise in weight measuring---calm down.

Was wondering if anyone has any experience to bring to bear on these hypotheses!

Cheers,
Andrew

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Re: Fitbit and gym for 2wk: Calorie deficit but no weight loss?

Postby Soupspoon » Mon Aug 21, 2017 4:33 pm UTC

My first thoughts (apart from 'noise') are that muscle density is about 20% more than fat. You could easily end up measurably slimmer and leaner, but wirier, and still weigh more.

I bet, even if it isn't (entirely) that redistribution, it's that kind of complication. And I'm not entirely sure "water retention" is actually a thing in most cases of such self-(mis)diagnosis (any more than "big boned" is) but at a density above that of fat (but below muscle) 'raw' water, and thus many of the physiological liquids, could also increase density. And therefore weight, perhaps even without obviously noticed bloating.

(IANAPhysiologist.)

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jobriath
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Re: Fitbit and gym for 2wk: Calorie deficit but no weight loss?

Postby jobriath » Thu Aug 24, 2017 3:58 pm UTC

Thanks for the reply!

Granted that muscle is denser than fat. I'm 99.9% confident (with the 0.1% being because IANAPhysicist) that removing energy from a system can't make it more massive, no matter the distribution of that energy, so if she really is losing 500kcal per day then fat/muscle wouldn't explain it. Her losing weight slower than expected then points either to her burning something more energy dense than fat (muscle? eek), the possibility that she isn't losing 500kcal, or noise in the form of water/waste/the-scales-being-terrible variation.

Oh well, noise will disappear over time and she seems to be gaining muscle. Fingers crossed for weigh-in three, on Monday.

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Re: Fitbit and gym for 2wk: Calorie deficit but no weight loss?

Postby doogly » Thu Aug 24, 2017 6:39 pm UTC

There is a lot of noise in weight measurements. How often is she measuring? If you are weighing every day consistently, it may be possible to notice a line sloping its way through a scatter plot, but two weeks is still pretty short, especially if you also have lady times cycling with a wavelength longer than your current sampling width, so who knows really.

I'd definitely recommend doing weigh ins more frequently than weekly though. Heck, multiple times a day! It's the best way to deal with noise. I think some people do it less often because there is some stress about scales, or they don't want to stress about how the sausage is being made (or unmade, in this case?) but it's good for noticing past noise. I mean if the expectation is you want to lose a pound of real body fat in a week, but you can sweat out a pound of moisture overnight* or in a good piss**, you are searching for signal in a very rough place.

But, if as you said she seems to be gaining muscle, then this is great ultimate victory! Measurable progress is really great. Maybe she can toss an extra 5 pounds on a bench beyond last week. That is totally dope and while scales tell you all sorts of nonsense, The Iron Doesn't Lie.

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Re: Fitbit and gym for 2wk: Calorie deficit but no weight loss?

Postby 4=5 » Sun Aug 27, 2017 1:36 am UTC

jobriath wrote:Granted that muscle is denser than fat. I'm 99.9% confident (with the 0.1% being because IANAPhysicist) that removing energy from a system can't make it more massive, no matter the distribution of that energy

Try calculating some examples to check your intuition. (muscle is about 1.33 lbs per 1000 calories. fat is about 0.3 lbs per 1000 calories)

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Re: Fitbit and gym for 2wk: Calorie deficit but no weight loss?

Postby nightbird » Sat Sep 16, 2017 8:03 am UTC

Keep in mind that our body consists of 80% water. Therefore, water retention caused by carbs/salty foods/muscle soreness/hormones (menstrual cycle) can change your bodyweight by several pounds.

Here's my advice to her: weigh yourself everyday to get many data points. Keep in mind that 1kg of actual bodyfat is 7000 calories, so if she gains 0.2kg overnight it's just water. Make a graph - if it slowly goes down over the course of several weeks, she's doing great. If it stops moving for two weeks or more, reassess the calories.
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Re: Fitbit and gym for 2wk: Calorie deficit but no weight loss?

Postby jobriath » Wed Sep 27, 2017 2:35 pm UTC

Thank you all. The concept of frequent weighing in order to handle noise is advice I've seen elsewhere too. It sounds like excellent advice, well posed.

Thanks again!


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